1. Field of the Invention
The invention relates to a conveying device for extended line products, such as cables or tubes, which has a conveying device housing and parallel running, driveable endless roller chains. A number of collet chucks are mounted on the roller chains to grip the extended line product. Each roller chain extends around a stationary driving chain wheel and a tension chain wheel in an endless drive path. The tension chain wheels are located in bearing housings and can move together with the bearing housings, with respect to the driving chain wheels, to tension the endless roller chains.
2. Description of the Prior Art
A conveying device for extended line products, for example for welded tubes, is known from the February 1992 publication "Uniwema Machines and Accessories" by Kabelmetal Electro GmbH. With this known conveying device, the roller chains, on which the collet chucks are mounted, must be manually retensioned, because of the wear caused during operation. If this retensioning is not timely performed, the roller chains are too loose on the chain wheels thereby increasing the wear of the roller chains and chain wheels.
If a collet chuck gripping the extended line product opens while the extended line product is being pulled, e.g. by a corrugated sheath machine, the next collet chuck in the drive direction of the roller chains must supply a larger portion of the required pulling force on the extended line product. If the roller chains are insufficiently tensioned in this operating instance, the sudden tension forces caused by the increased pulling force on the extended line product produces sudden changes in velocity thereof in the driving direction of the roller chains. These changes in velocity of the pulled-off extended line product could possibly produce manufacturing defects, such as welding defects in the extended line product, when using a known conveying device in a universal corrugated sheath machine in accordance with the above cited publication.
Furthermore, with manual retensioning of the roller chains, there is the danger of overstressing the roller chains.